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I have over a 5 years of experience in designing, developing, and maintaining R/Shiny applications for data exploration, analysis and reporting. I also build (and maintain) data, analytical and modeling workflows in R and Python.…

Jacek Cieslar

Data Scientist, Web Developer, Full Stack Developer, +2

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I have over a 5 years of experience in designing, developing, and maintaining R/Shiny applications for data exploration, analysis and reporting. I also build (and maintain) data, analytical and modeling workflows in R and Python.…

Available to hire

I have over a 5 years of experience in designing, developing, and maintaining R/Shiny applications for data exploration, analysis and reporting.
I also build (and maintain) data, analytical and modeling workflows in R and Python.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Language

Polish

Fluent

English

Fluent

Spanish; Castilian

Beginner

Work Experience

Freelance R/Shiny and Python Developer at Self-Employed

February 1, 2026 - Present

Designing, developing and maintaining R/Shiny analytical apps. Building data, analytical and modeling workflows in R/Python. Creating and maintaining R packages and Python modules. Implementing CI/CD pipelines and containerized deployments using Docker.

Software Developer, Senior Data Scientist at Kantar S.A.

October 1, 2019 - December 1, 2024

Designing, developing and maintaining analytical apps (Shiny), and ETL and data modeling processes (R/Python). Communicating and collaborating with project managers, business analysts and other dev teams. General data science and analytics.

Senior Researcher at Zymetria

December 1, 2018 - September 1, 2019

Quantitative analysis and reporting. Data processing. Study design and management.

Senior Client Executive, Research Manager at Kantar S.A.

August 1, 2012 - December 1, 2018

Quantitative analysis and reporting. Study design and coordination. Local, international and cross-country project management.

Analyst, Junior Analyst, Intern at Kantar S.A.

October 1, 2007 - July 1, 2012

Quantitative analysis and reporting. Study design and coordination. Local, international and cross-country project management.

Research Assistant at Institute of Political Studies of the Polish Academy of Sciences

September 1, 2014 - August 1, 2017

Collecting, processing and analysing data. Participation in writing scientific papers.